Speed-up mechanism for an injection molding machine

Abstract

A speed-up mechanism for an injection molding machine has a front fixed plate having a through hole at the center; a rear fixed plate arranged parallel with the front fixed plate, and the rear fixed plate having at least one through hole; at least two guide bars parallel to each other arranged between the front fixed plate and the rear fixed plate in an equal distance; a movable plate slidably arranged on the guide bars between the front fixed plate and the rear fixed plate, and capable of moving toward and away; a rotary power source fixed on one side of the movable plate for providing rotary power, the rotatry power source comprising a transmission device; a fixed nut mounted on the rear fixed plate; at least one ball screw having two threads in opposite directions at two ends, the front end is engaged with the transmission device for generating a radial rotation, the rear end is engage with the fixed nut and through the rear fixed plate to generate an axial movement for the ball screw during the rotation; and at least one movable nut engaged with the front end of the ball screw to move along the ball screw during the rotation of the ball screw, the outside of the movable nut is connected to the movable plate to drive the movable plate in the axial direction during the rotation of the ball screw.

What is claimed is:  
     
       1. A speed-up mechanism for an injection molding machine, comprising: 
       a front fixed plate having a through hole at a center thereof;  
       a rear fixed plate arranged parallel with the front fixed plate, and having at least one through hole;  
       at least two parallel guide bars arranged between the front fixed plate and the rear fixed plate;  
       a movable plate slidably arranged on the guide bars between the front fixed plate and the rear fixed plate, and capable of moving toward and away the front fixed plate a the rear fixed plate;  
       and rotary power source fixed on one side of the movable plate for providing rotary power, and having a transmission device;  
       a fixed nut mounted on the rear fixed plate;  
       at least one ball screw having a front end and a rear end, and having two threads extending in opposite thread directions, one of the threads being disposed at the front end, and another of the threads being disposed at the rear end the front end being engaged with the transmission device so that the transmission device causes the ball screw to rotate the rear end being engaged with the fixed nut so that when the ball screw is rotated, the ball screw is moved in an axial direction; and  
       at least one movable nut engaged with the front end of the ball screw to move along the ball screw during the rotation of the ball screw, an outside of the movable nut being connected to the movable plate to drive the movable plate in the axial direction during the rotation of he ball screw.  
     
     
       2. The speed-up mechanism as claimed in  claim 1 , wherein when the rotary power source rotates the ball screw, via the transmission device, in a predetermined direction relative to the fixed nut on the rear fixed plate, the movable nut causes the movable plate to be driven on the guide bars. 
     
     
       3. The speed-up mechanism as claimed in  claim 1 , wherein the threads on the two ends of he ball screw have the same lead. 
     
     
       4. The speed-up mechanism as claimed in  claim 1 , wherein the rotary power source is a servomotor. 
     
     
       5. The speed-up mechanism as claimed in  claim 1 , wherein the rotary power source is an induction motor. 
     
     
       6. The speed-up mechanism as claimed in  claim 1 , wherein the rotary power source is an oil pressure motor. 
     
     
       7. The speed-up mechanism as claimed in  claim 1 , wherein the front of the ball screw is connected to a transmission rod. 
     
     
       8. The speed-up mechanism as claimed in  claim 7 , wherein the transmission device comprises a timing belt and a conical constrictive ring, and an output shaft of the rotary power source further comprises a driving wheel, the transmission rod connected to the front end of the ball screw further comprises a driven wheel, so rotary power from the driving wheel of the rotary power source is transmitted to the driven wheel via the timing belt and the a conical constrictive ring of the transmission device. 
     
     
       9. The speed-up mechanism as claimed in  claim 2 , wherein the transmission device is a gear combination. 
     
     
       10. A speed-up mechanism for an injection molding machine, comprising: 
       a front fixed plate having a through hole at a center thereof;  
       a rear fixed plate arranged parallel with the front fixed plate, and having at least one through hole;  
       at least two guide bars arranged between the front fixed plate and the rear fixed plate;  
       a movable plate slidably arranged on the guide bars between the front fixed plate and the rear fixed plate, and capable of moving toward and away the front fixed plate and the rear fixed plate;  
       a fixed nut mounted on the rear fixed plate; a ball screw having front end and a rear end, and having two threads extending in opposite direction, one of the threads being disposed at the front end, and another of the threads being disposed at the rear end, the front end being engageable with a transmission device for causing the ball screw to rotate the rear end being engaged with the fixed nut so that when the ball screw is rotated, the ball screw is moved in an axial direction; and  
       a movable nut engaged with the front end of the ball screw to move along the ball screw during the rotation of the ball screw an outside of the movable nut being connected to the movable plate to drive the movable plate in the axial direction during the rotation of the ball screw.  
     
     
       11. The speed-up mechanism as claimed in  claim 10 , wherein the threads on the two ends of the all screw have the same lead. 
     
     
       12. The speed-up mechanism as claimed in  claim 10 , wherein the front of the ball screw is connected to a transmission rod.